Unveiling the fundamental understanding of two dimensional π-conjugated FeN 4+4 sites for boosting peroxymonosulfate activation

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-05, Vol.12 (19), p.11310-11321
• Main Authors: Jin, Sijia, Tan, Wenxian, Tang, Xiaofeng, Yao, Xia, Bao, Yingjian, Zhang, Haiyan, Song, Shuang, Zeng, Tao
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D4TA01195C

The absence of periodic structures and uncertainty concerning active sites in traditional single-atom catalysts (SACs) consistently impede the understanding of the coordination environment and its impact on the peroxymonosulfate (PMS) activation mechanism. In this study, we develop well-defined FeN 4+4 active-site configurations featuring robust and ordered N-coordinated Fe single-atomic centers within fully π-conjugated polyphthalocyanine frameworks (CPFs). CPF–FeN 4+4 functions as an outstanding PMS activator, exhibiting remarkable efficiency in the degradation of bisphenol A (BPA) with a rate constant of 1.87 min −1 , surpassing the majority of state-of-the-art SAC-based PMS systems. Mechanistic scrutiny unveils heightened chemisorption and electron transfer dynamics between PMS and CPF–FeN 4+4 , facilitating a 1 O 2 -dominated selective oxidation pathway. The distinctive FeN 4+4 active sites, integrated into π-conjugated frameworks, expedite S–O bond cleavage in PMS, thereby reducing the energy barrier for the formation of *HSO 3 and *O 2 ( 1 O 2 precursors). The charge redistribution in CPF–FeN 4+4 engenders a dual-pump-driven, electron-fast shuttle path, involving electron-rich Fe centers and electron-poor C surrounding adjacent benzene rings, ensuring the continuous production of 1 O 2 . This study not only delineates precise active sites at the atomic level for PMS activation but also advances the evolution of a highly promising catalytic oxidation system tailored for practical environmental purification.